1. Field of the Invention
The present invention relates to a contact switch, specifically to a position responsive switch for a water pump.
2. Description of the Related Art
Position sensitive switches have been utilized to turn on and off a light upon the opening and closing of the electrical circuit state. A quantity of mercury was usually used as the movable conductor; the mercury is gravity responsive and reacts to either completing or disconnecting the circuit state. However, mercury is now considered a hazardous material and the use should be avoided, due to the environmental and health concerns. The use of position sensitive switches has many different applications; this application refers to liquid level sensing switches. Liquid level sensing switches are important to know that a proper liquid level is being maintained. If the liquid level is not maintained usually, the liquid level sensing switch will turn on a pump to extract the necessary level of liquid to return the liquid level to a normal state. Nevertheless, liquid level sensing switches have been limited in application due to the relative size of the switch, the expense of the switch, and the switch reliability. Some improvements have been made in the field. Examples of references related to the present invention are described below, and the supported teachings of each reference are incorporated by reference herein:
U.S. Pat. No. 5,208,430, issued to Ludzia, discloses a position responsive switch having a ball received within a hollow cylindrical conductor. Depended upon the position of the switch, the ball may contact only the hollow cylindrical conductor or it may also contact a second conductor to complete a circuit between the two conductors. The cylindrical conductor and ball are enclosed in a two-part insulating housing, including a hollow member having one closed end, and a cap for closing the open end of the hollow member. Electrical leads are connected to the two conductors through the closed end of the hollow housing member.
U.S. Pat. No. 3,934,103, issued to Walstra, discloses a liquid level sensing switch that has an open ended chamber in an electrically conductive body, has an insulating bushing disposed in the open end of the body chamber and has a contact member extending through the bushing to dispose one end of the contact member in spaced relation to the body at the closed end of the body chamber. An electrically conductive magnetizable ball is disposed in the chamber for movement between a closed circuit position engaging both the body and the contact member and an open circuit position spaced from one of these components. A float is mounted on the body exteriorly of the chamber and carries a magnet so that movement of the float between two positions outside the body in response to change in liquid level is effective to move the ball between open and closed circuit positions within the body chamber.
U.S. Pat. No. 5,543,767, issued to Elenbaas, discloses an electrical switch functioning as a tilt, proximity or relay switch that includes an elongate cylindrical housing with a first open end and a second closed end. A flexible spring extends longitudinally in the housing and is supported away from the housing by a seal at the open end. The housing and spring are electrically conductive and an electrically-conductive spherical ball is located within the housing for selective rolling engagement with the spring and housing. The switch functions as a single pole single throw type switch. A second spring can be located at the closed second end of the housing and supported similar to the first spring. By locating the spherical ball between the two springs, a single pole double throw switch is formed.
U.S. Pat. No. 5,530,428, issued to Woods, discloses a magnetic switch assembly that is provided for detecting relative movement between first and second adjacent members, and to defeat attempted magnetic manipulation of the assembly. The assembly includes a pair of adjacent, superposed, upper and lower switch elements adapted for mounting on the first member, with the lower switch element presenting a sloped surface. A shiftable, ferromagnetic ball is disposed between the elements and movable along surface between spaced upper and lower switch operating positions. A magnet adapted for mounting on the second member is also provided, and is oriented for normally retaining the ball in the upper position thereof; however, upon movement of the member, the ball is permitted to shift downwardly along the sloped surface to the lower switch operating position thereof. Attempted magnetic manipulation via external magnet also causes the ball to shift from the upper to the lower position thereof. The respective switch assemblies are capable defeating attempted external magnetic manipulation as ball traverses transversely oriented elongated paths of travel responsive to external magnetic forces.
U.S. Pat. No. 5,457,293, issued to Breed, discloses a unique geometry that is used to amplify the force created by gravity on a tilting mass to substantially increase the resulting contact force in a mechanical tilt switch. In some cases a novel contact surface containing abrasive particles is also used to substantially reduce the contact force required to achieve a low contact resistance. The combination of these two features permits a substantial reduction in the size of the seismic mass needed for mechanical tilt switches and results in a switch which has a comparable size and comparable performance to mercury switches without the use of mercury. In some applications the effect of vibration is reduced by partially filling the switch housing with a damping fluid.
U.S. Patent Application Publication No.: 2003/0016106, by Woods, discloses an improved magnetic switch that is provided which is designed for use in an alarm circuit in order to detect relative movement between first and second members such as a door and frame, so as to signal unauthorized opening of the door. The switch includes a switch assembly for mounting in frame and having first and second switch elements, a permanently magnetized, shiftable body adjacent the elements, and a first attractive component. Additionally, the switch has a second attractive component for mounting to the door, which is in the form of a ferromagnetic component such as a permanent magnet or steel plate. In use when door is closed and circuit is armed, the magnetic attraction between body and component shifts the body to a switch-closed position in simultaneous contact with the switch elements. If the door is opened, the magnetic attraction between body and component moves the body to a switch-open position out of simultaneous contact with the switch elements, thus triggering circuit. If an intruder attempts to defeat the switch through an external magnet, this again moves the body to a switch-open position, triggering the circuit.
The inventions heretofore known suffer from a number of disadvantages which include being expensive, being non-durable, being not long lasting, and being unreliable.
What is needed is a steel ball contact switch that solves one or more of the problems described herein and/or one or more problems that may come to the attention of one skilled in the art upon becoming familiar with this specification.